The global medical device electrode market which includes primarily ECG (Electrocardiogram), EEG (Electroenchephalogram), EMG (Electromyogram), EOG (Electrooculogram), ENG (Dectroneurogram), TENS (Transcutaneous electrical nerve stimulation) and DBS (Deep brain stimulation) among others, is a highly mature, price sensitive and competitive industry. Current technology limits the effective electrode-tissue interface to enhance sensitivity towards recording and stimulation capabilities for both acute and chronic bio-signal acquisition. The sensitivity and signal to noise ratio (SNR) of neural recordings and the rate of current discharge of the electrode can and should be improved.
Various medical treatments involving electrical stimulation of neural tissue have been used for years and the breadth of treatments is expanding. Prior art electrodes are generally based on inert metals, limiting the capacity of the electrodes. For example, single Pt electrodes have capacities of approximately 300-350 mC/cm2. In order to increase the sensitivity of the electrode and record from a single neuron, the size of the electrode would most likely have to be in the micrometer range. However, as the size of the electrode is decreased, the impedance increases, resulting in poor signal to noise ratio.
Polymer coated electrodes have lower impedance, however the polymers are often fragile and have weak adhesion to the electrode substrate. What is needed is a highly conductive, low impedance, durable electrode that has high biocompatibility.